Investigation on the inhibition of Campylobacter jejuni growth with the applications of some preservatives, medicines, herbs and herb preparations.

The aim of this study was to determine the influence of chosen preservatives, medicines, herbs and herb preparations on 39 Campylobacter jejuni strains, which were isolated from fresh poultry carcasses. De-Nol and ventrisol were used in the original concentration. Propolis, propolan, artecholin and aukalen were of pharmacies origin. The rest of substances examined were 10% water solutions. Out of 11 substances examined, potassium sorbate, sodium benzoate, De-Nol and ventrisol exerted the strongest inhibitory action on Campylobacter jejuni.

[Tests of Helicobacter pylori survival in milk]. / Badania przezywalnosci Helicobacter pylori w mleku.

The survival of microaerophilic bacteria Helicobacter pylori (Hp) isolated from gastric mucosa was studied in 2 ml and 10 ml samples of milk contaminated with a suspension of these bacteria in 20% glucose solution. Milk was kept at 5-7 degrees C temperature in refrigerator and at room temperature. Hp was found in samples kept at 5-7 degrees C during 3 days. On the other hand, Hp was not found after 24-hours keeping at room temperature.

[Rappaport--Vassiliadis medium--a new liquid selectively-multiplying medium for detection of Salmonella in food]. / Pozywka rappaport--vassiliadis--nowe plynne podloze wybiórczo-namnazajace do wykrywania paleczek Salmonella w zywnosci.

On the basis of the available literature, the history of development of the Rappaport--Vassiliadis (RV) medium, its preparation and applicability in food control methods were described. Results of comparative studies on the effectiveness of Salmonella isolation upon use of different specifically-multiplying media: MK, medium containing sodium acid selenite, R25/37 degrees C, RV, were presented. The number of Salmonella isolations in samples multiplied in RV medium was found to exceed that obtained upon use of the remaining media. Moreover, RV medium was easy to prepare; it proved to be economical and was stable for up to 7 months when refrigerated.

[Effect of preincubation time and concentration of selective media on the effectiveness of salmonella organism isolation from frozen meat homogenates]. / Wplyw czasu przednamnazania oraz stezenia pozywek wybiórczo-namnazajacych na efektywnosc izolacji paleczek Salmonlla z homogenizatów miesa mrozonego.

Double concentrated RV and SC media were used for selective multiplication of frozen meat homogenates preincubated in buffered peptone water during 6 and 20 hours. It was found that cultures of 2 ml of homogenate preincubated during 6 hours in 10 ml of twofold concentrated RV medium, and selective multiplication during 20 hours made possible obtaining of a greater number of Salmonella isolates as compared to samples preincubated during 20 hours and transferred in volumes of 0.1 ml into 10 ml of normal concentration medium. On the other hand, the growth of 1 ml of a culture preincubated during 6 hours transferred into 10 ml of twofold concentrated SC medium yielded a similar number of salmonella isolates as in the case of samples preincubated during 24 h and transferred in 1 ml volumes into 10 ml of the SC medium without concentration change.

[Modification of the test for determining bacterial capacity for nitrate reduction]. / Modyfikacja testu okreslania zdolnosci bakterii do redukcji azotanów.

For facilitation of the detection of bacteria able to reduce nitrates the presently used method of 24-hour broth culture with KNO3 and the method of growing on slant agar cultures with KNO3 (standard method) were compared, with certain modifications introduced. It was found that shortening of the incubation period from 24 to 6 hours and reduction of the volume of broth with KNO3 from 10 to 0.5 ml made possible obtaining of a greater number of correct results as compared to the standard method. In the 24-hour broth cultures with KNO3 done as yet in case of negative results it is indispensable to confirm them in the test with zinc dust. The placement of Griess reagents on points onto colonies growing on KNO3 agar may lead to false positive results.

[Effect of glucose and swine blood on the effectiveness of the "SK" medium]. / Wplyw glukozy i krwi wieprozowej na efektywnosc podloza "SK".

The effectiveness of the "SK" medium for growth of bacteria producing green discoloration in cured meat products was examined with the addition of various amounts of glucose (0.0%, 0.01%, 0.05%, 0.1%, 0.5% and 1.0%), pig blood (0.0%, 2.5% and 5.0%). It was found that pig blood in the medium was indispensable for growth and differentiation of the green-producing bacteria, and that its optimum concentration is 5%. The effectiveness of the medium was with addition of 0.1% glucose.

Transfer Volume-Dependent Recovery of Salmonella from Minced Meat.

Six hundred 25-g samples of ground beef were divided into 3 groups of 200 each and 1 drop of a Salmonella broth culture was added to each sample. After storage at -27°C for 3-4 months, the samples were defrosted and blended with 225 ml of buffered peptone water. Ten ml of each suspension was preenriched at 37°C for 20 h and 10-fold dilutions of the material were made. One ml each of the preenriched culture and dilutions of 10-2, 10-4, 10-6, and 10-8 were transferred to selective enrichment media, and subsequently streaked onto selective agar plates. The mean percentage of Salmonella -positives obtained from all combinations of the selective media in relation to undiluted preenriched material and its 10-2, 10-4, 10-6, and 10-8 dilutions were for Salmonella typhimurium 70, 81, 84, 37, and 2, for Salmonella choleraesuis 64, 78, 66, 30, and 2, and for Salmonella anatum 60, 84, 75, 40, and 1, respectively. Colonies originating from diluted samples, particularly 10-4 and further dilutions, usually represented pure cultures of salmonellae, but from undiluted material were frequently accompanied or outgrown by concomitant bacteria.

Effect of a Short Cold Storage on Frequency of Spoilage in Pasteurized (Perishable) Canned Meat Products Subjected to the Incubation Test.

Investigations were carried out in 6 meat processing plants in Poland on the effect of a short storage period on the results of the incubation test of various canned pasteurized meat products. From the daily consignments, 1% of the cans was reserved within 1-3 d of production and incubated at 37°C for 3 d. The remaining cans of the consignments were stored at around 8°C. When spoilage resulted in one or more of the incubated cans from any consignment, about 2% of other cans from that consignment were taken, and the incubation test was repeated. These later incubation tests were initiated 7-10 d after the date of production. From among 4,322 cans subjected to first incubation test 980 (22.67%) produced swells but in the repeated incubation carried out on 8,290 cans only 347 (4.18%) became swollen. It is concluded that the bacteria responsible for spoilage of canned pasteurized meat products may disappear or lose their ability to spoil these products during the storage under refrigeration.

Effects of Preenrichment Media and Their Incubation Conditions on Isolating Salmonellae from Fish Meal.

Various combinations of preenrichment media, their incubation times and temperatures and atmospheres were examined for their efficacy in recovering salmonellae naturally occurring in fish meal. Variations included three preenrichment media (lactose broth, lactose broth supplemented with 10% defibrinated horse blood, and lactose broth with 10% egg yolk), three (25, 37 and 43 C) incubation temperatures, two (24 and 48 h) incubation times, and two (aerobic and anaerobic) incubation atmospheres. Three hundred and twenty samples (50 g each) of various consignments of fish meal known to be contaminated with salmonellae were examined. The lowest number (282) of isolations of salmonellae was obtained using lactose broth for preenrichment. Lactose broth with addition of blood gave 321 isolations, and lactose broth with egg yolk 357 isolations. In general, advantage was observed for preenrichment for 48 h (504) over preenrichment for 24 h (456). This was particularly evident at 25 C with 201 and 144 isolations, respectively. However. at 43 C the results were reverse (135 isolations after 48 h. and 156 after 24 h). At 37 C not so significant differences were found (168 - 48 h, and 156 - 24 h). Salmonellae were isolated 345 times with preenrichment at 25 C. 324 times at 37 C and 291 times at 43 C. Anaerobic preenrichment gave more (510) positives as compared with aerobic preenrichment (450 positives).

Veterinary public health activities aiming at prevention of chemical and other residues in food of animal origin. Action at the processing level.

The present situation regarding chemical residues in food products of animal origin is discussed. Some suggestions are given for sanitary judgement of such products and for preventive actions to be taken by the veterinary services.

Effects of enrichment media and incubation conditions on isolating salmonellae from ground-meat filtrate.

Forty-eight combinations of enrichment media, secondary enrichment, incubation times and temperatures, and atmospheres were examined for their efficacy in recovering different serovars of Salmonella that had been inoculated into ground-meat extract. Variations included three selective-enrichment media, two (37 and 43 degrees C) incubation temperatures, two (24 and 48 h) incubation times, two (aerobic and anaerobic) incubation atmospheres, and secondary enrichment to two of the selective-enrichment media. The ratio of Salmonella to other microorganisms was 10: greater than 1,000,000. One-hundred and twenty-four tests were conducted for each enrichment under each condition of incubation. None of the methods recovered Salmonella in more than 60% of the trials. Salmonella typhimurium was recovered most frequently of the serovars tested; S. abortusovis was recovered least frequently. There was considerable variation in the results obtained by the different methods, but there was a statistically significant advantage in the 43 degrees C incubation temperature. Secondary enrichment in tetrathionate broth showed a statistically significant advantage over secondary enrichment in selenite broth. Secondary enrichment into a different medium from the primary enrichment also was advantageous.